package simple;

import java.util.HashMap;
import java.util.Map;
import java.util.PriorityQueue;
import java.util.Scanner;

/**
 * MT7 字符编码
 * @author d3y1
 */
public class MT7{
    public static void main(String[] args){
        Scanner in = new Scanner(System.in);

        while(in.hasNext()) {
            solution(in);
        }
    }

    /**
     * 优先队列: 哈夫曼编码
     * @param in
     */
    private static void solution(Scanner in){
        String str = in.nextLine();

        Map<Character, Integer> charCountMap = new HashMap<>();
        for(char ch: str.toCharArray()){
            charCountMap.put(ch, charCountMap.getOrDefault(ch, 0)+1);
        }

        PriorityQueue<Integer> queue = new PriorityQueue<>();
        for(int value : charCountMap.values()){
            queue.offer(value);
        }

        int result = 0;
        while(queue.size() >= 2) {
            int a = queue.poll();
            int b = queue.poll();
            result += a+b;
            queue.offer(a+b);
        }

        System.out.println(result);
    }
}